Interannual differences in the regressions of the polar caps of Mars

Analyses of the behavior of the Martian polar caps in the recent spacecraft and ground based observations seem to reveal the existence of year to year variations on their regressions. In order to investigate the interannual differences in the regressions of the polar caps, the earlier data by Fischbacher et al., were reexamined, which were based on the measurements of the large number of high quality photographic plates and films collected from 1905 to 1965 at the Lowell Observatory. The results are reported and discussed

Protein Kinase C Activity in Mouse Eggs Regulates Gamete Membrane Interaction

Every mammalian life develops from one cell after fertilization of an egg by the sperm. The molecular pathways governing this event are still poorly understood. Numerous reports indicate that mammalian eggs highly express various protein kinase C (PKC) isoforms. Accordingly, we hypothesize that PKC activity in the egg plays an important role during egg-sperm membrane binding and fusion. In this study, we tested our hypothesis in mouse gametes using two types of PKC inhibitors (calphostin c and staurosporine) and the typical PKC activator, phorbol ester 12-tetradecanoylphorbol-13 acetate (PMA). After treatment with the individual drug, eggs were inseminated with sperm. The sperm binding number (SB) and fusion rate (FR) were scored using light and fluorescence microscopy. By applying the Student’s t-test, we confirmed that the FR and SB were significantly decreased after PKC activator or inhibitors treatments. All treatment groups, 1 μM calphostin c, 1 μM staurosporine, or 1 nM PMA showed the significant reduction of FR and SB. Further analysis indicated that the inhibition effects of calphostin c and PMA were dose- and time- dependent. Moreover, under scanning electron microscopy (SEM), we observed that the number and shape of microvilli on the PMA-treated eggs, but not on the calphostin c-treated eggs, was severely changed. Taken together, these results suggest that egg PKC activity plays an important role in the signaling regulation of sperm-egg membrane binding and fusion during fertilization

月の海の進化と陸の成長

京都大学0048新制・論文博士理学博士乙第2980号論理博第523号新制||理||226(附属図書館)4742UT51-61-I212(主査)教授 宮本 正太郎, 教授 川口 市郎, 教授 加藤 正二学位規則第5条第2項該当Kyoto UniversityDA

Felling by a Five-Legged Walking Machine

A 1/11 scale model of a walking machine with five legs was constructed, and its operation as a feller-buncher investigated. As slopes steepen, the machine when positioned straight up the slope becomes more efficient than when positioned parallel to the contour lines, because the downward operational range of the machine decreases with increased slopes. In the experiments, the ground pressure of the legs on the end opposite the boom was nearly zero when the boom holding felled trees was positioned at the side of the body and extended farthest from the body. However, further investigations (including such factors as ground disturbance, the operation of the machine, the degrees and the length of slope, and the fuel consumption) of felling operations are needed. Feller-bunching tends to be less efficient as tree density increases assuming that felling time per tree remains constant as tree diameter changes. To obtain greater productivity with the machine as a feller-buncher, it is essential to achieve faster walking-time and shorter felling-time per tree

Non-Thermal Continuum toward SGRB2(N-LMH)

An analysis of continuum antenna temperatures observed in the Green Bank Telescope (GBT) spectrometer bandpasses is presented for observations toward SgrB2(N-LMH). Since 2004, we have identified four new prebiotic molecules toward this source by means of rotational transitions between low energy levels; concurrently, we have observed significant continuum in the GBT spectrometer bandpasses centered at 85 different frequencies in the range of 1 to 48 GHz. The continuum heavily influences the molecular spectral features since we have observed far more absorption lines than emission lines for each of these new molecular species. Hence, it is important to understand the nature, distribution, and intensity of the underlying continuum in the GBT bandpasses for the purposes of radiative transfer, i.e. the means by which reliable molecular abundances are estimated. We find that the GBT spectrometer bandpass continuum is consistent with optically-thin, non thermal (synchrotron) emission with a flux density spectral index of -0.7 and a Gaussian source size of ~143" at 1 GHz that decreases with increasing frequency as nu^(-0.52). Some support for this model is provided by high frequency Very Large Array (VLA) observations of SgrB2.Comment: Accepted for Publication in the Astrophysical Journal Letter

Hierarchization of the decision-making process according to the economic sector

The objective is to delineate a hierarchical model of decisions and respective management indicators. In an everyday universe of events that occur, if considers a purpose of the organization can face a hierarchy of decisions, from major strategic to minor ones. Such a finding, if delineated as a model, it can be useful in the study of decision-making process. For this analysis was adopted a multiple case study method applied in commercial, industrial and service organization. Afterwards was maximized with a differentiated sample of managers selection to be interviewed according to the organizational pyramid hierarchical rank as structured bases; meetings with key opinion groups; available preliminary data collection directly from the websites. As a result, a hierarchical decision model was obtained, differentiated according to the acting economic segment

Ribosome Rescue and Translation Termination at Non-Standard Stop Codons by ICT1 in Mammalian Mitochondria

Release factors (RFs) govern the termination phase of protein synthesis. Human mitochondria harbor four different members of the class 1 RF family: RF1Lmt/mtRF1a, RF1mt, C12orf65 and ICT1. The homolog of the essential ICT1 factor is widely distributed in bacteria and organelles and has the peculiar feature in human mitochondria to be part of the ribosome as a ribosomal protein of the large subunit. The factor has been suggested to rescue stalled ribosomes in a codon-independent manner. The mechanism of action of this factor was obscure and is addressed here. Using a homologous mitochondria system of purified components, we demonstrate that the integrated ICT1 has no rescue activity. Rather, purified ICT1 binds stoichiometrically to mitochondrial ribosomes in addition to the integrated copy and functions as a general rescue factor, i.e. it releases the polypeptide from the peptidyl tRNA from ribosomes stalled at the end or in the middle of an mRNA or even from non-programmed ribosomes. The data suggest that the unusual termination at a sense codon (AGA/G) of the oxidative-phosphorylation enzymes CO1 and ND6 is also performed by ICT1 challenging a previous model, according to which RF1Lmt/mtRF1a is responsible for the translation termination at non-standard stop codons. We also demonstrate by mutational analyses that the unique insertion sequence present in the N-terminal domain of ICT1 is essential for peptide release rather than for ribosome binding. The function of RF1mt, another member of the class1 RFs in mammalian mitochondria, was also examined and is discussed

Learn from history : Lessons from early modern Japanese physics experiment textbooks

The aim of our study is to explore the early history of the education of physics experiments in the Meiji era of Japan (1868 - 1912). In this paper, we examine three Japanese physics experiment textbooks which were published during 1880s. One characteristic feature is that the most of the experiments could be performed using simple handmade apparatuses. We consider what can be learned from the ingenuity of physics education pioneers of the late 19th century